It is known that one of the proteins forming the outer membrane complex of Chlamydia trachomatis, the major outer membrane protein (MOMP), is able to induce both T-cell responses and neutralizing antibodies against chlamydial infection in mammals, such as humans. A schematic overview of the MOMP protein is shown in FIG. 1, adapted from Findlay H E, McClafferty H & Ashley R H (2005) Surface expression, single-channel analysis and membrane topology of recombinant Chlamydia trachomatis major outer membrane protein. BMC Microbiology 5, 5, an article in which the topology of the MOMP protein was elucidated. In FIG. 1, A denotes the cell membrane and B denotes the outer surface of the cell membrane.
Use of the total MOMP protein as a vaccine against Chlamydia trachomatis has been disclosed in WO 2008/040757 A1.
However, animal experiments have shown very limited success of anti-chlamydial MOMP subunit vaccines. Furthermore, the production of the whole MOMP protein is tedious and expensive, not to mention limited to certain specific production methods.
To overcome the abovementioned deficiency, it has been suggested to use synthetic peptides, which combine specific epitopes from Chlamydia trachomatis, which epitopes trigger an immune response.
However, such isolated epitopes may not be functional in a synthetic context and thus not provide the desired effect.
Hence, an improved polypeptide for producing an immune response which is protective against Chlamydia trachomatis would be advantageous and in particular a polypeptide allowing for increased flexibility, cost-effectiveness, simplicity of production and purification with retained or improved immunological effect would be advantageous.